How do I iterate through a specific xpath against an XmlDocument that has no prefix/namespace ?
I'm parsing XML like so :
var doc = new XmlDocument();
doc.LoadXml(input);
var nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace(nsPrefix, ns);
var nodes = doc.SelectNodes(xpath, nsmgr);
This works totally fine when the nsPrefix as well as the ns are passed in and non-empty.
However, when the namespace/prefix are empty for example in this scenario:
Then I am unable to correctly parse the XML.
The full function is:
public static class XPathWalker
{
public static IEnumerable<string> GetListOfAttachments(string input, string xpath, string nsPrefix, string ns)
{
var doc = new XmlDocument();
doc.LoadXml(input);
var nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace(nsPrefix, ns);
var nodes = doc.SelectNodes(xpath, nsmgr);
foreach (XmlNode node in nodes)
{
if (string.IsNullOrWhiteSpace(node.InnerText))
{
continue;
}
yield return node.InnerText;
}
}
}
How do I iterate through a specific xpath against an XmlDocument that has no prefix/namespace ?
There was indeed a way to do this with XmlDocument. Firstly, I had to convert the input string to a stream:
// convert string to stream
byte[] byteArray = Encoding.UTF8.GetBytes(input);
MemoryStream stream = new MemoryStream(byteArray);
Once I had my stream, I was able to feed it into XmlDocument. Here's the full code:
string input = #"<?xml version="1.0" encoding="UTF-8"?>etc..";
byte[] byteArray = Encoding.UTF8.GetBytes(input);
var stream = new MemoryStream(byteArray);
var doc = new XmlDocument();
var nodes = doc.SelectNodes(xpath);
using (var tr = new XmlTextReader(stream))
{
tr.Namespaces = false;
doc.Load(tr);
}
Related
How can I write an XML file so that it starts a new line and does not overwrite the previous data?
string pfad = "C:\\temp\\Accounts.xml";
XmlDocument doc = new XmlDocument();
XmlElement root = doc.CreateElement("Login");
XmlElement id = doc.CreateElement("user");
XmlElement username = doc.CreateElement("username");
username.InnerText = txtBenutzerName.Text;
id.AppendChild(username);
root.AppendChild(id);
doc.AppendChild(root);
doc.Save(pfad);
MessageBox.Show("Created SuccesFully!");
Instead of creating a new document by this line
XmlDocument doc = new XmlDocument();
you should load existing file like this:
XmlDocument doc = new XmlDocument();
doc.Load(pfad);
...below code is the same...
XmlDocument doc = new XmlDocument();
doc.Load("C:\\Accounts.xml");
doc.GetElementsByTagName("username")[0].InnerText="sdkjfsdknfkds";
doc.Save("C:\\Accounts.xml");
I'm working on some code to read an XML fragment which contains an XML declaration, e.g. <?xml version="1.0" encoding="utf-8"?> and parse the encoding. From MSDN, I should be able to do it like this:
var nt = new NameTable();
var mgr = new XmlNamespaceManager(nt);
var context = new XmlParserContext(null, mgr, null, XmlSpace.None);
var reader = new System.Xml.XmlTextReader(#"<?xml version=""1.0"" encoding=""UTF-8""?>",
System.Xml.XmlNodeType.XmlDeclaration, context);
However, I'm getting a System.Xml.XmlException on the call to the System.Xml.XmlTextReader constructor with an error message:
XmlNodeType XmlDeclaration is not supported for partial content
parsing.
I've googled this error in quotes -- exactly zero results found (edit: now there's one result: this post) -- and without quotes, which yields nothing useful. I've also looked at MSDN for the XmlNodeType, and it doesn't say anything about it not being supported.
What am I missing here? How can I get an XmlTextReader instance from an XML declaration fragment?
Note, my goal here is just to determine the encoding of a partially-built XML document where I'm making the assumption that it at least contains a declaration node; thus, I'm trying to get reader.Encoding. If there's another way to do that, I'm open to that.
At present, I'm parsing the declaration manually using regex, which is not the best approach.
Update: Getting the encoding from XML documentation or from XML fragment:
Here's a way to get the encoding without having to resort to fake root, using XmlReader.Create.
private static string GetXmlEncoding(string xmlString)
{
if (string.IsNullOrWhiteSpace(xmlString)) throw new ArgumentException("The provided string value is null or empty.");
using (var stringReader = new StringReader(xmlString))
{
var settings = new XmlReaderSettings { ConformanceLevel = ConformanceLevel.Fragment };
using (var xmlReader = XmlReader.Create(stringReader, settings))
{
if (!xmlReader.Read()) throw new ArgumentException(
"The provided XML string does not contain enough data to be valid XML (see https://msdn.microsoft.com/en-us/library/system.xml.xmlreader.read)");
var result = xmlReader.GetAttribute("encoding");
return result;
}
}
}
Here's the output, with a full and fragment XML:
If you want to have System.Text.Encoding, you can modify the code to look like this:
private static Encoding GetXmlEncoding(string xmlString)
{
using (StringReader stringReader = new StringReader(xmlString))
{
var settings = new XmlReaderSettings { ConformanceLevel = ConformanceLevel.Fragment };
var reader = XmlReader.Create(stringReader, settings);
reader.Read();
var encoding = reader.GetAttribute("encoding");
var result = Encoding.GetEncoding(encoding);
return result;
}
}
Old answer:
As you mentioned, XmlTextReader's Encoding-property contains the encoding.
Here's a full Console app's source code which hopefully is useful:
class Program
{
static void Main(string[] args)
{
var asciiXML = #"<?xml version=""1.0"" encoding=""ASCII""?><note><to>Tove</to><from>Jani</from><heading>Reminder</heading><body>Don't forget me this weekend!</body></note>";
var utf8XML = #"<?xml version=""1.0"" encoding=""UTF-8""?><note><to>Tove</to><from>Jani</from><heading>Reminder</heading><body>Don't forget me this weekend!</body></note>";
var asciiResult = GetXmlEncoding(asciiXML);
var utfResult = GetXmlEncoding(utf8XML);
Console.WriteLine(asciiResult);
Console.WriteLine(utfResult);
Console.ReadLine();
}
private static Encoding GetXmlEncoding(string s)
{
var stream = new MemoryStream(Encoding.UTF8.GetBytes(s));
using (var xmlreader = new XmlTextReader(stream))
{
xmlreader.MoveToContent();
var encoding = xmlreader.Encoding;
return encoding;
}
}
}
Here's the output from the program:
If you know that the XML only contains the declaration, maybe you can add an empty root? So for example:
var fragmentResult = GetXmlEncoding(xmlFragment + "<root/>");
Good evening, here's the solution with a System.Text.Encoding as output.
I made it to be clear, and step by step.
class Program
{
static void Main(string[] args)
{
var line = File.ReadLines(YourFileName).First();
var correctXml = line + "<Root></Root>";
var xml = XDocument.Parse(correctXml);
var stringEncoding = xml.Declaration.Encoding;
var encoding = System.Text.Encoding.GetEncoding(stringEncoding);
}
}
Maybe late but you can use below code after loading it in a XmlDocument
static string getEncoding(XmlDocument xml)
{
if (xml.FirstChild.NodeType == XmlNodeType.XmlDeclaration)
{
return (xml.FirstChild as XmlDeclaration).Encoding;
}
return "utf-8";
}
If you have a byte array as input, try something like this:
private Encoding getEncoding(byte[] data)
{
XmlReaderSettings settings = new XmlReaderSettings();
settings.DtdProcessing = DtdProcessing.Ignore;
XmlDocument doc = new XmlDocument();
MemoryStream ms = new MemoryStream(data);
XmlReader reader = XmlReader.Create(ms, settings);
doc.Load(reader);
XmlDeclaration declaration = doc.ChildNodes.OfType<XmlDeclaration>().FirstOrDefault();
return Encoding.GetEncoding(declaration.Encoding);
}
I'm converting a JSON string to an XML node like this:
public ActionResult Test(string json)
{
System.Xml.XmlNode myXmlNode = JsonConvert.DeserializeXmlNode("{\"root\":" + json + "}", "root");
How can I save myXmlNode to an external file, say test.xml?
Thanks
This should do it:
var xdoc = XDocument.Load(new StringReader(myXmlNode.ToString()), LoadOptions.None);
xdoc.Save(#"c:\temp\test.xml", SaveOptions.None);
UPDATE:
using (StreamWriter writer = new StreamWriter(Server.MapPath("~/test.xml")))
{
writer.WriteLine(myXmlNode.OuterXml);
}
XmlDocument doc = new XmlDocument();
doc.LoadXml(myXmlNode);
XmlTextWriter writer = new XmlTextWriter("yourfilename.xml",null);
writer.Formatting = Formatting.Indented;
doc.Save(writer);
I have some xml data that looks like..
<Root>
<Data>Nack</Data>
<Data>Nelly</Data>
</Root>
I want to add "<?xml version=\"1.0\"?>" to this string. Then preserve the xml as a string.
I attempted a few things..
This breaks and loses the original xml string
myOriginalXml="<?xml version=\"1.0\"?>" + myOriginalXml;
This doesnt do anything, just keeps the original xml data with no declaration attached.
XmlDocument doc = new XmlDocument();
doc.LoadXml(myOriginalXml);
XmlDeclaration declaration = doc.CreateXmlDeclaration("1.0", "UTF-8","no");
StringWriter sw = new StringWriter();
XmlTextWriter tx = new XmlTextWriter(sw);
doc.WriteTo(tx);
string xmlString = sw.ToString();
This is also not seeming to have any effect..
XmlDocument doc = new XmlDocument();
doc.LoadXml(myOriginalXml);
XmlDeclaration declaration = doc.CreateXmlDeclaration("1.0", "UTF-8", "no");
MemoryStream xmlStream = new MemoryStream();
doc.Save(xmlStream);
xmlStream.Flush();
xmlStream.Position = 0;
doc.Load(xmlStream);
StringWriter sw = new StringWriter();
XmlTextWriter tx = new XmlTextWriter(sw);
doc.WriteTo(tx);
string xmlString = sw.ToString();
Use an xmlwritersettings to achieve greater control over saving. The XmlWriter.Create accepts that setting (instead of the default contructor)
var myOriginalXml = #"<Root>
<Data>Nack</Data>
<Data>Nelly</Data>
</Root>";
var doc = new XmlDocument();
doc.LoadXml(myOriginalXml);
var ms = new MemoryStream();
var tx = XmlWriter.Create(ms,
new XmlWriterSettings {
OmitXmlDeclaration = false,
ConformanceLevel= ConformanceLevel.Document,
Encoding = UTF8Encoding.UTF8 });
doc.Save(tx);
var xmlString = UTF8Encoding.UTF8.GetString(ms.ToArray());
I have the following variable that accepts a file name:
var xtr = new XmlTextReader(xmlFileName) { WhitespaceHandling = WhitespaceHandling.None };
var xd = new XmlDocument();
xd.Load(xtr);
I would like to change it so that I can pass in an object. I don't want to have to serialize the object to file first.
Is this possible?
Update:
My original intentions were to take an xml document, merge some xslt (stored in a file), then output and return html... like this:
public string TransformXml(string xmlFileName, string xslFileName)
{
var xtr = new XmlTextReader(xmlFileName) { WhitespaceHandling = WhitespaceHandling.None };
var xd = new XmlDocument();
xd.Load(xtr);
var xslt = new System.Xml.Xsl.XslCompiledTransform();
xslt.Load(xslFileName);
var stm = new MemoryStream();
xslt.Transform(xd, null, stm);
stm.Position = 1;
var sr = new StreamReader(stm);
xtr.Close();
return sr.ReadToEnd();
}
In the above code I am reading in the xml from a file. Now what I would like to do is just work with the object, before it was serialized to the file.
So let me illustrate my problem using code
public string TransformXMLFromObject(myObjType myobj , string xsltFileName)
{
// Notice the xslt stays the same.
// Its in these next few lines that I can't figure out how to load the xml document (xd) from an object, and not from a file....
var xtr = new XmlTextReader(xmlFileName) { WhitespaceHandling = WhitespaceHandling.None };
var xd = new XmlDocument();
xd.Load(xtr);
}
You want to turn an arbitrary .NET object into a serialized XML string? Nothing simpler than that!! :-)
public string SerializeToXml(object input)
{
XmlSerializer ser = new XmlSerializer(input.GetType(), "http://schemas.yournamespace.com");
string result = string.Empty;
using(MemoryStream memStm = new MemoryStream())
{
ser.Serialize(memStm, input);
memStm.Position = 0;
result = new StreamReader(memStm).ReadToEnd();
}
return result;
}
That should to it :-) Of course you might want to make the default XML namespace configurable as a parameter, too.
Or do you want to be able to create an XmlDocument on top of an existing object?
public XmlDocument SerializeToXmlDocument(object input)
{
XmlSerializer ser = new XmlSerializer(input.GetType(), "http://schemas.yournamespace.com");
XmlDocument xd = null;
using(MemoryStream memStm = new MemoryStream())
{
ser.Serialize(memStm, input);
memStm.Position = 0;
XmlReaderSettings settings = new XmlReaderSettings();
settings.IgnoreWhitespace = true;
using(var xtr = XmlReader.Create(memStm, settings))
{
xd = new XmlDocument();
xd.Load(xtr);
}
}
return xd;
}
You can serialize directly into the XmlDocument:
XmlDocument doc = new XmlDocument();
XPathNavigator nav = doc.CreateNavigator();
using (XmlWriter w = nav.AppendChild())
{
XmlSerializer ser = new XmlSerializer(typeof(MyType));
ser.Serialize(w, myObject);
}
Expanding on #JohnSaunders solution I wrote the following generic function:
public XmlDocument SerializeToXml<T>(T source) {
var document = new XmlDocument();
var navigator = document.CreateNavigator();
using (var writer = navigator.AppendChild()) {
var serializer = new XmlSerializer(typeof(T));
serializer.Serialize(writer, source);
}
return document;
}